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diff --git a/ffmpeg/doc/muxers.texi b/ffmpeg/doc/muxers.texi deleted file mode 100644 index 776ba2b..0000000 --- a/ffmpeg/doc/muxers.texi +++ /dev/null @@ -1,960 +0,0 @@ -@chapter Muxers -@c man begin MUXERS - -Muxers are configured elements in FFmpeg which allow writing -multimedia streams to a particular type of file. - -When you configure your FFmpeg build, all the supported muxers -are enabled by default. You can list all available muxers using the -configure option @code{--list-muxers}. - -You can disable all the muxers with the configure option -@code{--disable-muxers} and selectively enable / disable single muxers -with the options @code{--enable-muxer=@var{MUXER}} / -@code{--disable-muxer=@var{MUXER}}. - -The option @code{-formats} of the ff* tools will display the list of -enabled muxers. - -A description of some of the currently available muxers follows. - -@anchor{aiff} -@section aiff - -Audio Interchange File Format muxer. - -It accepts the following options: - -@table @option -@item write_id3v2 -Enable ID3v2 tags writing when set to 1. Default is 0 (disabled). - -@item id3v2_version -Select ID3v2 version to write. Currently only version 3 and 4 (aka. -ID3v2.3 and ID3v2.4) are supported. The default is version 4. - -@end table - -@anchor{crc} -@section crc - -CRC (Cyclic Redundancy Check) testing format. - -This muxer computes and prints the Adler-32 CRC of all the input audio -and video frames. By default audio frames are converted to signed -16-bit raw audio and video frames to raw video before computing the -CRC. - -The output of the muxer consists of a single line of the form: -CRC=0x@var{CRC}, where @var{CRC} is a hexadecimal number 0-padded to -8 digits containing the CRC for all the decoded input frames. - -For example to compute the CRC of the input, and store it in the file -@file{out.crc}: -@example -ffmpeg -i INPUT -f crc out.crc -@end example - -You can print the CRC to stdout with the command: -@example -ffmpeg -i INPUT -f crc - -@end example - -You can select the output format of each frame with @command{ffmpeg} by -specifying the audio and video codec and format. For example to -compute the CRC of the input audio converted to PCM unsigned 8-bit -and the input video converted to MPEG-2 video, use the command: -@example -ffmpeg -i INPUT -c:a pcm_u8 -c:v mpeg2video -f crc - -@end example - -See also the @ref{framecrc} muxer. - -@anchor{framecrc} -@section framecrc - -Per-packet CRC (Cyclic Redundancy Check) testing format. - -This muxer computes and prints the Adler-32 CRC for each audio -and video packet. By default audio frames are converted to signed -16-bit raw audio and video frames to raw video before computing the -CRC. - -The output of the muxer consists of a line for each audio and video -packet of the form: -@example -@var{stream_index}, @var{packet_dts}, @var{packet_pts}, @var{packet_duration}, @var{packet_size}, 0x@var{CRC} -@end example - -@var{CRC} is a hexadecimal number 0-padded to 8 digits containing the -CRC of the packet. - -For example to compute the CRC of the audio and video frames in -@file{INPUT}, converted to raw audio and video packets, and store it -in the file @file{out.crc}: -@example -ffmpeg -i INPUT -f framecrc out.crc -@end example - -To print the information to stdout, use the command: -@example -ffmpeg -i INPUT -f framecrc - -@end example - -With @command{ffmpeg}, you can select the output format to which the -audio and video frames are encoded before computing the CRC for each -packet by specifying the audio and video codec. For example, to -compute the CRC of each decoded input audio frame converted to PCM -unsigned 8-bit and of each decoded input video frame converted to -MPEG-2 video, use the command: -@example -ffmpeg -i INPUT -c:a pcm_u8 -c:v mpeg2video -f framecrc - -@end example - -See also the @ref{crc} muxer. - -@anchor{framemd5} -@section framemd5 - -Per-packet MD5 testing format. - -This muxer computes and prints the MD5 hash for each audio -and video packet. By default audio frames are converted to signed -16-bit raw audio and video frames to raw video before computing the -hash. - -The output of the muxer consists of a line for each audio and video -packet of the form: -@example -@var{stream_index}, @var{packet_dts}, @var{packet_pts}, @var{packet_duration}, @var{packet_size}, @var{MD5} -@end example - -@var{MD5} is a hexadecimal number representing the computed MD5 hash -for the packet. - -For example to compute the MD5 of the audio and video frames in -@file{INPUT}, converted to raw audio and video packets, and store it -in the file @file{out.md5}: -@example -ffmpeg -i INPUT -f framemd5 out.md5 -@end example - -To print the information to stdout, use the command: -@example -ffmpeg -i INPUT -f framemd5 - -@end example - -See also the @ref{md5} muxer. - -@anchor{gif} -@section gif - -Animated GIF muxer. - -It accepts the following options: - -@table @option -@item loop -Set the number of times to loop the output. Use @code{-1} for no loop, @code{0} -for looping indefinitely (default). - -@item final_delay -Force the delay (expressed in centiseconds) after the last frame. Each frame -ends with a delay until the next frame. The default is @code{-1}, which is a -special value to tell the muxer to re-use the previous delay. In case of a -loop, you might want to customize this value to mark a pause for instance. -@end table - -For example, to encode a gif looping 10 times, with a 5 seconds delay between -the loops: -@example -ffmpeg -i INPUT -loop 10 -final_delay 500 out.gif -@end example - -Note 1: if you wish to extract the frames in separate GIF files, you need to -force the @ref{image2} muxer: -@example -ffmpeg -i INPUT -c:v gif -f image2 "out%d.gif" -@end example - -Note 2: the GIF format has a very small time base: the delay between two frames -can not be smaller than one centi second. - -@anchor{hls} -@section hls - -Apple HTTP Live Streaming muxer that segments MPEG-TS according to -the HTTP Live Streaming specification. - -It creates a playlist file and numbered segment files. The output -filename specifies the playlist filename; the segment filenames -receive the same basename as the playlist, a sequential number and -a .ts extension. - -@example -ffmpeg -i in.nut out.m3u8 -@end example - -@table @option -@item -hls_time @var{seconds} -Set the segment length in seconds. -@item -hls_list_size @var{size} -Set the maximum number of playlist entries. -@item -hls_wrap @var{wrap} -Set the number after which index wraps. -@item -start_number @var{number} -Start the sequence from @var{number}. -@end table - -@anchor{ico} -@section ico - -ICO file muxer. - -Microsoft's icon file format (ICO) has some strict limitations that should be noted: - -@itemize -@item -Size cannot exceed 256 pixels in any dimension - -@item -Only BMP and PNG images can be stored - -@item -If a BMP image is used, it must be one of the following pixel formats: -@example -BMP Bit Depth FFmpeg Pixel Format -1bit pal8 -4bit pal8 -8bit pal8 -16bit rgb555le -24bit bgr24 -32bit bgra -@end example - -@item -If a BMP image is used, it must use the BITMAPINFOHEADER DIB header - -@item -If a PNG image is used, it must use the rgba pixel format -@end itemize - -@anchor{image2} -@section image2 - -Image file muxer. - -The image file muxer writes video frames to image files. - -The output filenames are specified by a pattern, which can be used to -produce sequentially numbered series of files. -The pattern may contain the string "%d" or "%0@var{N}d", this string -specifies the position of the characters representing a numbering in -the filenames. If the form "%0@var{N}d" is used, the string -representing the number in each filename is 0-padded to @var{N} -digits. The literal character '%' can be specified in the pattern with -the string "%%". - -If the pattern contains "%d" or "%0@var{N}d", the first filename of -the file list specified will contain the number 1, all the following -numbers will be sequential. - -The pattern may contain a suffix which is used to automatically -determine the format of the image files to write. - -For example the pattern "img-%03d.bmp" will specify a sequence of -filenames of the form @file{img-001.bmp}, @file{img-002.bmp}, ..., -@file{img-010.bmp}, etc. -The pattern "img%%-%d.jpg" will specify a sequence of filenames of the -form @file{img%-1.jpg}, @file{img%-2.jpg}, ..., @file{img%-10.jpg}, -etc. - -The following example shows how to use @command{ffmpeg} for creating a -sequence of files @file{img-001.jpeg}, @file{img-002.jpeg}, ..., -taking one image every second from the input video: -@example -ffmpeg -i in.avi -vsync 1 -r 1 -f image2 'img-%03d.jpeg' -@end example - -Note that with @command{ffmpeg}, if the format is not specified with the -@code{-f} option and the output filename specifies an image file -format, the image2 muxer is automatically selected, so the previous -command can be written as: -@example -ffmpeg -i in.avi -vsync 1 -r 1 'img-%03d.jpeg' -@end example - -Note also that the pattern must not necessarily contain "%d" or -"%0@var{N}d", for example to create a single image file -@file{img.jpeg} from the input video you can employ the command: -@example -ffmpeg -i in.avi -f image2 -frames:v 1 img.jpeg -@end example - -@table @option -@item start_number @var{number} -Start the sequence from @var{number}. Default value is 1. Must be a -non-negative number. - -@item -update @var{number} -If @var{number} is nonzero, the filename will always be interpreted as just a -filename, not a pattern, and this file will be continuously overwritten with new -images. - -@end table - -The image muxer supports the .Y.U.V image file format. This format is -special in that that each image frame consists of three files, for -each of the YUV420P components. To read or write this image file format, -specify the name of the '.Y' file. The muxer will automatically open the -'.U' and '.V' files as required. - -@section matroska - -Matroska container muxer. - -This muxer implements the matroska and webm container specs. - -The recognized metadata settings in this muxer are: - -@table @option - -@item title=@var{title name} -Name provided to a single track -@end table - -@table @option - -@item language=@var{language name} -Specifies the language of the track in the Matroska languages form -@end table - -@table @option - -@item stereo_mode=@var{mode} -Stereo 3D video layout of two views in a single video track -@table @option -@item mono -video is not stereo -@item left_right -Both views are arranged side by side, Left-eye view is on the left -@item bottom_top -Both views are arranged in top-bottom orientation, Left-eye view is at bottom -@item top_bottom -Both views are arranged in top-bottom orientation, Left-eye view is on top -@item checkerboard_rl -Each view is arranged in a checkerboard interleaved pattern, Left-eye view being first -@item checkerboard_lr -Each view is arranged in a checkerboard interleaved pattern, Right-eye view being first -@item row_interleaved_rl -Each view is constituted by a row based interleaving, Right-eye view is first row -@item row_interleaved_lr -Each view is constituted by a row based interleaving, Left-eye view is first row -@item col_interleaved_rl -Both views are arranged in a column based interleaving manner, Right-eye view is first column -@item col_interleaved_lr -Both views are arranged in a column based interleaving manner, Left-eye view is first column -@item anaglyph_cyan_red -All frames are in anaglyph format viewable through red-cyan filters -@item right_left -Both views are arranged side by side, Right-eye view is on the left -@item anaglyph_green_magenta -All frames are in anaglyph format viewable through green-magenta filters -@item block_lr -Both eyes laced in one Block, Left-eye view is first -@item block_rl -Both eyes laced in one Block, Right-eye view is first -@end table -@end table - -For example a 3D WebM clip can be created using the following command line: -@example -ffmpeg -i sample_left_right_clip.mpg -an -c:v libvpx -metadata stereo_mode=left_right -y stereo_clip.webm -@end example - -This muxer supports the following options: - -@table @option - -@item reserve_index_space -By default, this muxer writes the index for seeking (called cues in Matroska -terms) at the end of the file, because it cannot know in advance how much space -to leave for the index at the beginning of the file. However for some use cases --- e.g. streaming where seeking is possible but slow -- it is useful to put the -index at the beginning of the file. - -If this option is set to a non-zero value, the muxer will reserve a given amount -of space in the file header and then try to write the cues there when the muxing -finishes. If the available space does not suffice, muxing will fail. A safe size -for most use cases should be about 50kB per hour of video. - -Note that cues are only written if the output is seekable and this option will -have no effect if it is not. - -@end table - -@anchor{md5} -@section md5 - -MD5 testing format. - -This muxer computes and prints the MD5 hash of all the input audio -and video frames. By default audio frames are converted to signed -16-bit raw audio and video frames to raw video before computing the -hash. - -The output of the muxer consists of a single line of the form: -MD5=@var{MD5}, where @var{MD5} is a hexadecimal number representing -the computed MD5 hash. - -For example to compute the MD5 hash of the input converted to raw -audio and video, and store it in the file @file{out.md5}: -@example -ffmpeg -i INPUT -f md5 out.md5 -@end example - -You can print the MD5 to stdout with the command: -@example -ffmpeg -i INPUT -f md5 - -@end example - -See also the @ref{framemd5} muxer. - -@section mov/mp4/ismv - -MOV/MP4/ISMV (Smooth Streaming) muxer. - -The mov/mp4/ismv muxer supports fragmentation. Normally, a MOV/MP4 -file has all the metadata about all packets stored in one location -(written at the end of the file, it can be moved to the start for -better playback by adding @var{faststart} to the @var{movflags}, or -using the @command{qt-faststart} tool). A fragmented -file consists of a number of fragments, where packets and metadata -about these packets are stored together. Writing a fragmented -file has the advantage that the file is decodable even if the -writing is interrupted (while a normal MOV/MP4 is undecodable if -it is not properly finished), and it requires less memory when writing -very long files (since writing normal MOV/MP4 files stores info about -every single packet in memory until the file is closed). The downside -is that it is less compatible with other applications. - -Fragmentation is enabled by setting one of the AVOptions that define -how to cut the file into fragments: - -@table @option -@item -moov_size @var{bytes} -Reserves space for the moov atom at the beginning of the file instead of placing the -moov atom at the end. If the space reserved is insufficient, muxing will fail. -@item -movflags frag_keyframe -Start a new fragment at each video keyframe. -@item -frag_duration @var{duration} -Create fragments that are @var{duration} microseconds long. -@item -frag_size @var{size} -Create fragments that contain up to @var{size} bytes of payload data. -@item -movflags frag_custom -Allow the caller to manually choose when to cut fragments, by -calling @code{av_write_frame(ctx, NULL)} to write a fragment with -the packets written so far. (This is only useful with other -applications integrating libavformat, not from @command{ffmpeg}.) -@item -min_frag_duration @var{duration} -Don't create fragments that are shorter than @var{duration} microseconds long. -@end table - -If more than one condition is specified, fragments are cut when -one of the specified conditions is fulfilled. The exception to this is -@code{-min_frag_duration}, which has to be fulfilled for any of the other -conditions to apply. - -Additionally, the way the output file is written can be adjusted -through a few other options: - -@table @option -@item -movflags empty_moov -Write an initial moov atom directly at the start of the file, without -describing any samples in it. Generally, an mdat/moov pair is written -at the start of the file, as a normal MOV/MP4 file, containing only -a short portion of the file. With this option set, there is no initial -mdat atom, and the moov atom only describes the tracks but has -a zero duration. - -Files written with this option set do not work in QuickTime. -This option is implicitly set when writing ismv (Smooth Streaming) files. -@item -movflags separate_moof -Write a separate moof (movie fragment) atom for each track. Normally, -packets for all tracks are written in a moof atom (which is slightly -more efficient), but with this option set, the muxer writes one moof/mdat -pair for each track, making it easier to separate tracks. - -This option is implicitly set when writing ismv (Smooth Streaming) files. -@item -movflags faststart -Run a second pass moving the index (moov atom) to the beginning of the file. -This operation can take a while, and will not work in various situations such -as fragmented output, thus it is not enabled by default. -@item -movflags rtphint -Add RTP hinting tracks to the output file. -@end table - -Smooth Streaming content can be pushed in real time to a publishing -point on IIS with this muxer. Example: -@example -ffmpeg -re @var{<normal input/transcoding options>} -movflags isml+frag_keyframe -f ismv http://server/publishingpoint.isml/Streams(Encoder1) -@end example - -@section mp3 - -The MP3 muxer writes a raw MP3 stream with an ID3v2 header at the beginning and -optionally an ID3v1 tag at the end. ID3v2.3 and ID3v2.4 are supported, the -@code{id3v2_version} option controls which one is used. The legacy ID3v1 tag is -not written by default, but may be enabled with the @code{write_id3v1} option. - -For seekable output the muxer also writes a Xing frame at the beginning, which -contains the number of frames in the file. It is useful for computing duration -of VBR files. - -The muxer supports writing ID3v2 attached pictures (APIC frames). The pictures -are supplied to the muxer in form of a video stream with a single packet. There -can be any number of those streams, each will correspond to a single APIC frame. -The stream metadata tags @var{title} and @var{comment} map to APIC -@var{description} and @var{picture type} respectively. See -@url{http://id3.org/id3v2.4.0-frames} for allowed picture types. - -Note that the APIC frames must be written at the beginning, so the muxer will -buffer the audio frames until it gets all the pictures. It is therefore advised -to provide the pictures as soon as possible to avoid excessive buffering. - -Examples: - -Write an mp3 with an ID3v2.3 header and an ID3v1 footer: -@example -ffmpeg -i INPUT -id3v2_version 3 -write_id3v1 1 out.mp3 -@end example - -To attach a picture to an mp3 file select both the audio and the picture stream -with @code{map}: -@example -ffmpeg -i input.mp3 -i cover.png -c copy -map 0 -map 1 --metadata:s:v title="Album cover" -metadata:s:v comment="Cover (Front)" out.mp3 -@end example - -@section mpegts - -MPEG transport stream muxer. - -This muxer implements ISO 13818-1 and part of ETSI EN 300 468. - -The muxer options are: - -@table @option -@item -mpegts_original_network_id @var{number} -Set the original_network_id (default 0x0001). This is unique identifier -of a network in DVB. Its main use is in the unique identification of a -service through the path Original_Network_ID, Transport_Stream_ID. -@item -mpegts_transport_stream_id @var{number} -Set the transport_stream_id (default 0x0001). This identifies a -transponder in DVB. -@item -mpegts_service_id @var{number} -Set the service_id (default 0x0001) also known as program in DVB. -@item -mpegts_pmt_start_pid @var{number} -Set the first PID for PMT (default 0x1000, max 0x1f00). -@item -mpegts_start_pid @var{number} -Set the first PID for data packets (default 0x0100, max 0x0f00). -@item -mpegts_m2ts_mode @var{number} -Enable m2ts mode if set to 1. Default value is -1 which disables m2ts mode. -@item -muxrate @var{number} -Set muxrate. -@item -pes_payload_size @var{number} -Set minimum PES packet payload in bytes. -@item -mpegts_flags @var{flags} -Set flags (see below). -@item -mpegts_copyts @var{number} -Preserve original timestamps, if value is set to 1. Default value is -1, which -results in shifting timestamps so that they start from 0. -@item -tables_version @var{number} -Set PAT, PMT and SDT version (default 0, valid values are from 0 to 31, inclusively). -This option allows updating stream structure so that standard consumer may -detect the change. To do so, reopen output AVFormatContext (in case of API -usage) or restart ffmpeg instance, cyclically changing tables_version value: -@example -ffmpeg -i source1.ts -codec copy -f mpegts -tables_version 0 udp://1.1.1.1:1111 -ffmpeg -i source2.ts -codec copy -f mpegts -tables_version 1 udp://1.1.1.1:1111 -... -ffmpeg -i source3.ts -codec copy -f mpegts -tables_version 31 udp://1.1.1.1:1111 -ffmpeg -i source1.ts -codec copy -f mpegts -tables_version 0 udp://1.1.1.1:1111 -ffmpeg -i source2.ts -codec copy -f mpegts -tables_version 1 udp://1.1.1.1:1111 -... -@end example -@end table - -Option mpegts_flags may take a set of such flags: - -@table @option -@item resend_headers -Reemit PAT/PMT before writing the next packet. -@item latm -Use LATM packetization for AAC. -@end table - -The recognized metadata settings in mpegts muxer are @code{service_provider} -and @code{service_name}. If they are not set the default for -@code{service_provider} is "FFmpeg" and the default for -@code{service_name} is "Service01". - -@example -ffmpeg -i file.mpg -c copy \ - -mpegts_original_network_id 0x1122 \ - -mpegts_transport_stream_id 0x3344 \ - -mpegts_service_id 0x5566 \ - -mpegts_pmt_start_pid 0x1500 \ - -mpegts_start_pid 0x150 \ - -metadata service_provider="Some provider" \ - -metadata service_name="Some Channel" \ - -y out.ts -@end example - -@section null - -Null muxer. - -This muxer does not generate any output file, it is mainly useful for -testing or benchmarking purposes. - -For example to benchmark decoding with @command{ffmpeg} you can use the -command: -@example -ffmpeg -benchmark -i INPUT -f null out.null -@end example - -Note that the above command does not read or write the @file{out.null} -file, but specifying the output file is required by the @command{ffmpeg} -syntax. - -Alternatively you can write the command as: -@example -ffmpeg -benchmark -i INPUT -f null - -@end example - -@section ogg - -Ogg container muxer. - -@table @option -@item -page_duration @var{duration} -Preferred page duration, in microseconds. The muxer will attempt to create -pages that are approximately @var{duration} microseconds long. This allows the -user to compromise between seek granularity and container overhead. The default -is 1 second. A value of 0 will fill all segments, making pages as large as -possible. A value of 1 will effectively use 1 packet-per-page in most -situations, giving a small seek granularity at the cost of additional container -overhead. -@end table - -@section segment, stream_segment, ssegment - -Basic stream segmenter. - -The segmenter muxer outputs streams to a number of separate files of nearly -fixed duration. Output filename pattern can be set in a fashion similar to -@ref{image2}. - -@code{stream_segment} is a variant of the muxer used to write to -streaming output formats, i.e. which do not require global headers, -and is recommended for outputting e.g. to MPEG transport stream segments. -@code{ssegment} is a shorter alias for @code{stream_segment}. - -Every segment starts with a keyframe of the selected reference stream, -which is set through the @option{reference_stream} option. - -Note that if you want accurate splitting for a video file, you need to -make the input key frames correspond to the exact splitting times -expected by the segmenter, or the segment muxer will start the new -segment with the key frame found next after the specified start -time. - -The segment muxer works best with a single constant frame rate video. - -Optionally it can generate a list of the created segments, by setting -the option @var{segment_list}. The list type is specified by the -@var{segment_list_type} option. The entry filenames in the segment -list are set by default to the basename of the corresponding segment -files. - -The segment muxer supports the following options: - -@table @option -@item reference_stream @var{specifier} -Set the reference stream, as specified by the string @var{specifier}. -If @var{specifier} is set to @code{auto}, the reference is choosen -automatically. Otherwise it must be a stream specifier (see the ``Stream -specifiers'' chapter in the ffmpeg manual) which specifies the -reference stream. The default value is @code{auto}. - -@item segment_format @var{format} -Override the inner container format, by default it is guessed by the filename -extension. - -@item segment_list @var{name} -Generate also a listfile named @var{name}. If not specified no -listfile is generated. - -@item segment_list_flags @var{flags} -Set flags affecting the segment list generation. - -It currently supports the following flags: -@table @samp -@item cache -Allow caching (only affects M3U8 list files). - -@item live -Allow live-friendly file generation. -@end table - -@item segment_list_size @var{size} -Update the list file so that it contains at most the last @var{size} -segments. If 0 the list file will contain all the segments. Default -value is 0. - -@item segment_list_entry_prefix @var{prefix} -Set @var{prefix} to prepend to the name of each entry filename. By -default no prefix is applied. - -@item segment_list_type @var{type} -Specify the format for the segment list file. - -The following values are recognized: -@table @samp -@item flat -Generate a flat list for the created segments, one segment per line. - -@item csv, ext -Generate a list for the created segments, one segment per line, -each line matching the format (comma-separated values): -@example -@var{segment_filename},@var{segment_start_time},@var{segment_end_time} -@end example - -@var{segment_filename} is the name of the output file generated by the -muxer according to the provided pattern. CSV escaping (according to -RFC4180) is applied if required. - -@var{segment_start_time} and @var{segment_end_time} specify -the segment start and end time expressed in seconds. - -A list file with the suffix @code{".csv"} or @code{".ext"} will -auto-select this format. - -@samp{ext} is deprecated in favor or @samp{csv}. - -@item ffconcat -Generate an ffconcat file for the created segments. The resulting file -can be read using the FFmpeg @ref{concat} demuxer. - -A list file with the suffix @code{".ffcat"} or @code{".ffconcat"} will -auto-select this format. - -@item m3u8 -Generate an extended M3U8 file, version 3, compliant with -@url{http://tools.ietf.org/id/draft-pantos-http-live-streaming}. - -A list file with the suffix @code{".m3u8"} will auto-select this format. -@end table - -If not specified the type is guessed from the list file name suffix. - -@item segment_time @var{time} -Set segment duration to @var{time}, the value must be a duration -specification. Default value is "2". See also the -@option{segment_times} option. - -Note that splitting may not be accurate, unless you force the -reference stream key-frames at the given time. See the introductory -notice and the examples below. - -@item segment_time_delta @var{delta} -Specify the accuracy time when selecting the start time for a -segment, expressed as a duration specification. Default value is "0". - -When delta is specified a key-frame will start a new segment if its -PTS satisfies the relation: -@example -PTS >= start_time - time_delta -@end example - -This option is useful when splitting video content, which is always -split at GOP boundaries, in case a key frame is found just before the -specified split time. - -In particular may be used in combination with the @file{ffmpeg} option -@var{force_key_frames}. The key frame times specified by -@var{force_key_frames} may not be set accurately because of rounding -issues, with the consequence that a key frame time may result set just -before the specified time. For constant frame rate videos a value of -1/2*@var{frame_rate} should address the worst case mismatch between -the specified time and the time set by @var{force_key_frames}. - -@item segment_times @var{times} -Specify a list of split points. @var{times} contains a list of comma -separated duration specifications, in increasing order. See also -the @option{segment_time} option. - -@item segment_frames @var{frames} -Specify a list of split video frame numbers. @var{frames} contains a -list of comma separated integer numbers, in increasing order. - -This option specifies to start a new segment whenever a reference -stream key frame is found and the sequential number (starting from 0) -of the frame is greater or equal to the next value in the list. - -@item segment_wrap @var{limit} -Wrap around segment index once it reaches @var{limit}. - -@item segment_start_number @var{number} -Set the sequence number of the first segment. Defaults to @code{0}. - -@item reset_timestamps @var{1|0} -Reset timestamps at the begin of each segment, so that each segment -will start with near-zero timestamps. It is meant to ease the playback -of the generated segments. May not work with some combinations of -muxers/codecs. It is set to @code{0} by default. - -@item initial_offset @var{offset} -Specify timestamp offset to apply to the output packet timestamps. The -argument must be a time duration specification, and defaults to 0. -@end table - -@subsection Examples - -@itemize -@item -To remux the content of file @file{in.mkv} to a list of segments -@file{out-000.nut}, @file{out-001.nut}, etc., and write the list of -generated segments to @file{out.list}: -@example -ffmpeg -i in.mkv -codec copy -map 0 -f segment -segment_list out.list out%03d.nut -@end example - -@item -As the example above, but segment the input file according to the split -points specified by the @var{segment_times} option: -@example -ffmpeg -i in.mkv -codec copy -map 0 -f segment -segment_list out.csv -segment_times 1,2,3,5,8,13,21 out%03d.nut -@end example - -@item -As the example above, but use the @command{ffmpeg} @option{force_key_frames} -option to force key frames in the input at the specified location, together -with the segment option @option{segment_time_delta} to account for -possible roundings operated when setting key frame times. -@example -ffmpeg -i in.mkv -force_key_frames 1,2,3,5,8,13,21 -codec:v mpeg4 -codec:a pcm_s16le -map 0 \ --f segment -segment_list out.csv -segment_times 1,2,3,5,8,13,21 -segment_time_delta 0.05 out%03d.nut -@end example -In order to force key frames on the input file, transcoding is -required. - -@item -Segment the input file by splitting the input file according to the -frame numbers sequence specified with the @option{segment_frames} option: -@example -ffmpeg -i in.mkv -codec copy -map 0 -f segment -segment_list out.csv -segment_frames 100,200,300,500,800 out%03d.nut -@end example - -@item -To convert the @file{in.mkv} to TS segments using the @code{libx264} -and @code{libfaac} encoders: -@example -ffmpeg -i in.mkv -map 0 -codec:v libx264 -codec:a libfaac -f ssegment -segment_list out.list out%03d.ts -@end example - -@item -Segment the input file, and create an M3U8 live playlist (can be used -as live HLS source): -@example -ffmpeg -re -i in.mkv -codec copy -map 0 -f segment -segment_list playlist.m3u8 \ --segment_list_flags +live -segment_time 10 out%03d.mkv -@end example -@end itemize - -@section tee - -The tee muxer can be used to write the same data to several files or any -other kind of muxer. It can be used, for example, to both stream a video to -the network and save it to disk at the same time. - -It is different from specifying several outputs to the @command{ffmpeg} -command-line tool because the audio and video data will be encoded only once -with the tee muxer; encoding can be a very expensive process. It is not -useful when using the libavformat API directly because it is then possible -to feed the same packets to several muxers directly. - -The slave outputs are specified in the file name given to the muxer, -separated by '|'. If any of the slave name contains the '|' separator, -leading or trailing spaces or any special character, it must be -escaped (see @ref{quoting_and_escaping,,the "Quoting and escaping" -section in the ffmpeg-utils(1) manual,ffmpeg-utils}). - -Muxer options can be specified for each slave by prepending them as a list of -@var{key}=@var{value} pairs separated by ':', between square brackets. If -the options values contain a special character or the ':' separator, they -must be escaped; note that this is a second level escaping. - -The following special options are also recognized: -@table @option -@item f -Specify the format name. Useful if it cannot be guessed from the -output name suffix. - -@item bsfs[/@var{spec}] -Specify a list of bitstream filters to apply to the specified -output. - -It is possible to specify to which streams a given bitstream filter -applies, by appending a stream specifier to the option separated by -@code{/}. @var{spec} must be a stream specifier (see @ref{Format -stream specifiers}). If the stream specifier is not specified, the -bistream filters will be applied to all streams in the output. - -Several bitstream filters can be specified, separated by ",". - -@item select -Select the streams that should be mapped to the slave output, -specified by a stream specifier. If not specified, this defaults to -all the input streams. -@end table - -Some examples follow. -@itemize -@item -Encode something and both archive it in a WebM file and stream it -as MPEG-TS over UDP (the streams need to be explicitly mapped): -@example -ffmpeg -i ... -c:v libx264 -c:a mp2 -f tee -map 0:v -map 0:a - "archive-20121107.mkv|[f=mpegts]udp://10.0.1.255:1234/" -@end example - -@item -Use @command{ffmpeg} to encode the input, and send the output -to three different destinations. The @code{dump_extra} bitstream -filter is used to add extradata information to all the output video -keyframes packets, as requested by the MPEG-TS format. The select -option is applied to @file{out.aac} in order to make it contain only -audio packets. -@example -ffmpeg -i ... -map 0 -flags +global_header -c:v libx264 -c:a aac -strict experimental - -f tee "[bsfs/v=dump_extra]out.ts|[movflags=+faststart]out.mp4|[select=a]out.aac" -@end example - -@item -As below, but select only stream @code{a:1} for the audio output. Note -that a second level escaping must be performed, as ":" is a special -character used to separate options. -@example -ffmpeg -i ... -map 0 -flags +global_header -c:v libx264 -c:a aac -strict experimental - -f tee "[bsfs/v=dump_extra]out.ts|[movflags=+faststart]out.mp4|[select=\'a:1\']out.aac" -@end example -@end itemize - -Note: some codecs may need different options depending on the output format; -the auto-detection of this can not work with the tee muxer. The main example -is the @option{global_header} flag. - -@c man end MUXERS |